Sheet of complex, multi-layer material which can be used to produce protective clothing, particularly for fire fighters

ABSTRACT

This material is remarkable in that it is made by weaving or knitting, in such a manner as to form a structure comprising two superposed faces ( 1, 2 ) intermittently interconnected to each other so as to form pockets, and in which:  
     one of the layers shrinks under the effect of heat; and  
     the linking between the layers is implemented by intermittently linking selected yarns so as to form said pockets.

TECHNICAL FIELD

[0001] The present invention relates to cloth in sheet form for makingprotective garments, in particular working jackets for people in dangerof being subjected to extreme conditions, in particular in the event ofa fire.

[0002] The invention relates in particular to a novel type of materialsuitable for making garments for firefighters, although otherapplications are not excluded.

PRIOR ART

[0003] In the description below, the invention is described for aparticular application, namely that of making working jackets forfirefighters.

[0004] It is clear that this application is not limiting and that such amaterial could be used in other applications, whenever extremeconditions are present, e.g. during a fire.

[0005] At present, in order to make working jackets, multilayerstructures are used, which, as a general rule, and as can be seen inaccompanying FIG. 1, are made up in general of four elements:

[0006] an outer fabric (A);

[0007] a waterproof and breathing membrane, generally associated with asubstrate (B);

[0008] a thermal barrier generally constituted by a needled felt (C);and

[0009] a finishing lining (D).

[0010] The making of such laminated materials suitable for use underextreme conditions is well know to the person skilled in the art and canbe found in particular in French patent No. 1 213 415.

[0011] Such structures have subsequently evolved by making use inparticular of textile materials that withstand heat and fire, based onaromatic polyamides or on polyamide imide.

[0012] Amongst the better-known synthetic materials of this kind,mention can be made in the aromatic polyamide family of para-aramidfibers or yarns, such as those sold by the supplier Du Pont de Nemoursunder the name “Kevlar” or by the supplier Teijin under the trademark“Twaron” and “Technora”. Such polymers which may be in the form offibers, yarns, or other structures, constitute the subject matter ofnumerous publications, amongst which mention can be made of U.S. Pat.No. 3,063,966.

[0013] Amongst materials that also withstand heat, and which form partof the meta-aramid family, mention can be made of the polymer sold bythe supplier Kermel under its own name, the fibers sold under thetrademark “Nomex” by the supplier Du Pont de Nemours, and those soldunder the trademark “Conex” by the supplier Teijin.

[0014] As mentioned above, the invention thus relates to the field ofmaking multilayer materials of the kind shown in FIG. 1.

[0015] In such materials, a problem arises concerning the thermalbarrier which is generally constituted by a needled felt, and thefinishing lining which is situated on the user side thereof.

[0016] The laminates that have been proposed until now suffer from adrawback which lies essentially in the fact that the garments made fromthem are uncomfortable both physically and physiologically.

[0017] In addition, under certain circumstances, they are lacking ineffectiveness.

[0018] It has been reported that about 50% of the causes of firefighterdeath in the Untied States are the consequence of a phenomenon that iswell known in the field by the term “heat stress”, which is a state inwhich the body can no longer maintain a temperature below 39° C., andwhich leads to various disorders, which in addition to a loss ofphysical ability, can include loss of lucidity, fainting, or evencardiac arrest.

[0019] Such a stress state is caused in particular by the weight of theequipment carried which can exceed 20 kilograms (kg) and by theinsulating ability of the protective garments which can sometimes beexcessive.

SUMMARY OF THE INVENTION

[0020] It has been found, and this constitutes the subject matter of thepresent invention, that it is possible to solve this problem by making anovel type of material for prior art laminated structures of the typeshown in FIG. 1, which material serves to provide a thermal barrierfunction, and preferably also a finishing lining.

[0021] This new type of laminate, referred to herein by the term“thermal barrier”, provides moderate insulation under normalcircumstances because it is thin and presents small heat load, therebyimproving comfort, and as a function of increasing temperature, it alsomakes it possible to increase insulation, with such an increase possiblybeing localized in those zones where heat is greatest when the user isconfronted with an emergency situation by a fire.

[0022] In general, such a possibility is obtained with the material ofthe invention by making a laminate that performs simultaneously thethermal barrier and the finishing lining functions, by making use of atechnique for making woven cloth, which technique produces “pockets” orbonded double cloth.

[0023] Such technology consists in making two (or more) fabrics in asingle operation, which fabrics are distinct and superposed and areinterconnected by selecting yarns (warp or weft) which are engaged inalternation in a predetermined selection with one and with the other ofthe weaves of the two superposed fabrics.

[0024] By way of indication, a warp yarn of the top face may, in apredetermined sequence, be linked with a warp (or pick) yarn of thebottom face. This linking may be implemented using any type of pattern,and is conventionally used for forming lozenges or tubes.

[0025] In general, in the state of the art, the back and front faces ofdifferent colors are reversed to obtain a decorative effect, which isnot desirable in the context of the invention where each face needs tohave a specific function.

[0026] Such double-faced structures may optionally also be made byknitting, either using the sunk loop technique or the reinforcing looptechnique, more particularly on a Raschel or a warp type knittingmachine.

[0027] In general, and given the problem posed of providing a thermalbarrier for providing protection, in particular in the garments offirefighters, with the purpose of improving the comfort of such garmentsboth physically and physiologically, the invention provides a multilayerlaminated sheet material for providing a thermal barrier that is made upof a first layer and a second layer, the material being characterized inthat it is made by weaving or knitting, in such a manner as to form astructure comprising two superposed faces intermittently interconnectedto each other so as to form pockets, and in which:

[0028] one of the layers shrinks under the effect of heat; and

[0029] the linking between the layers is implemented by intermittentlylinking selected yarns so as to form said pockets.

[0030] Advantageously, the layer that shrinks under the effect of heatis constituted completely or in part by yarn that shrinks under saideffects of heat.

[0031] In a preferred embodiment, the pockets constitute channels, withshrinking under the effect of heat taking place only in the family ofyarns that extend perpendicularly to said channels, considered in fullor in part.

[0032] Without going beyond the ambit of the invention, the shrinkingeffect of the thermal barrier layer in question can result from thepresence of a membrane that is fixed to said layer, or from a coating.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention and the advantages it provides will be betterunderstood on reading the following description of an example of alaminate in accordance with the invention, and as shown in theaccompanying diagrams, in which:

[0034]FIG. 1, as described above, shows a conventional multilayerlaminate as used at present for making garments for personnel who takeaction under dangerous conditions, and in particular garments forfirefighters;

[0035]FIG. 2 is a perspective diagram showing an example of a structurefor a laminate enabling the thermal barrier and the finishing liningpresent in the above-mentioned laminate to be made simultaneously;

[0036]FIG. 3 is a diagrammatic section view of a material in accordancewith the invention when the user is in normal working conditions;

[0037]FIGS. 4 and 5 are a section view and a perspective view indiagrammatic form showing how the laminate of the invention changes whenthe user is confronted with a sudden change in working conditions, andmore particularly a sudden increase in heat;

[0038]FIG. 6 is a conventional diagram showing, on the left, adouble-faced cloth in accordance with the invention and, on the right,the fabric obtained on the front face (the lining face); and

[0039]FIG. 7 is a conventional diagram in section view in the warpdirection showing how the sheets of warp yarns are disposed relative tothe weft yarns in order to constitute a pocket type double-faced fabric,with the faces being linked to each other in a predetermined sequence.

[0040] With reference to accompanying FIGS. 2 and 3, the basic structurein accordance with the invention is thus constituted by a pocket fabriccomprising an inner layer given overall reference (1) and an outer layergiven an overall reference (2), these two layers being disposed next toeach other and being linked together intermittently by selected warpyarns (3), which yarns are selected from those that constitute the innerlayer.

[0041] In other words, in such a structure, the linking lines (3) formbetween them pockets that are flat and that extend between the innerlayer (1) and the outer layer (2).

[0042] In this example, and as can be seen more particularly in FIG. 2,the warp yarns (C1) that are for making the inner layer (1) on thelining side, and the weft yarns (T1) are both constituted by yarns, andmore particularly by spun yarns, of fibers that present practically noability to shrink under the effect of intense heat.

[0043] The warp yarns (C2) for constituting the outer layer (2) are madeof yarns that do indeed present some small ability to shrink comparedwith the yarns (C1). However, the weft yarns (T2) for constituting theouter layer are likewise based on spun yarns that present no ability toshrink.

[0044] In the specific example shown in FIG. 2, the density of warpyarns (C2) and of weft yarns (T2) is half that of the warp yarns (C1)and of the weft yarns (T1) of the other face.

[0045] By means of such a structure, the fact of using yarns in theouter layer that shrink a little when heated, makes it possible toobtain a reaction in the presence of heat of the kind shown in FIG. 4.

[0046] When the temperature reached by the outer layer (2) is high, e.g.when the warp yarns are made of meta-aramid yarns such as, for example:isostalamides and polyaramides, is a temperature of about 300° C., thenthe outer warp (C2) shrinks, thereby drawing together the generatorlines (3) defining the linkage zones. Since the layer (1) isdimensionally stable when heated, and since it is also protected in partby the outer layer, this leads to the inside being relaxed, and thus topockets being formed in relief.

[0047] It should be observed that even if (C1) and/or (T1) were made ofmaterials that present the ability to shrink, the fact that they areprotected in part by the face (2) would still create a temperaturedifference between the two faces and would thus lead to a shrinkagedifference that would create pockets in relief.

[0048] These spaces increase with increasing temperature, therebyincreasing the thickness of the laminate and trapping air, therebyincreasing the insulating ability of the material.

EXAMPLE

[0049] A laminate in accordance with the invention and of the type shownin FIG. 2 was made using the weave that is illustrated in FIG. 6.

[0050] The warp (C1) for forming the face that faces towards the user,and the weft (T1) likewise intended for forming said face, were madefrom a spun yarn of a mixture of fibers comprising polyamide imidefibers (Kermel) and viscose FR fibers (containing a fireproofing agent),in a 70/30 mixture, with the weight of these yarns being equal to Nm70/2.

[0051] This fabric face comprises 26 yarns/cm and 24 picks/cm.

[0052] The warp (C2) having the heat-shrinkability and constituting theinsulating layer was made of a spun yarn comprising 100% polyamide imidefibers sold under the trade name Kermel Tech, with the weight of thisyarn being Nm 60/2.

[0053] The density of the warp (C2) was 13 yarns/cm.

[0054] The weft (T2) was identical to the inner weft and its density was12 picks/cm.

[0055] On leaving the loom, the weight per unit area of the laminatedcloth was about 230 grams per square meter (g/m²).

[0056] The inner face (1) with greater structure is suitable for actingas a lining, and is the face that is directed towards the user. The face(2) made of heat-shrink yarns in its warp is the face that acts as athermal barrier.

[0057] Naturally, the embodiment described and shown of the multilayerlaminated material of the invention should not be considered as beinglimiting. The invention relates to any multilayer laminated material insheet form serving to make a thermal barrier comprising first and secondlayers by means of a structure comprising two superposed facesinterconnected intermittently so as to form pockets. The linking betweenthe layers is obtained by intermittent linking using selected yarns.

[0058] One of the layers shrinks under the effect of heat. In theexample shown, this shrinkage is obtained over all or part of the linkyarns constituting the pockets.

[0059] This effect of one of the layers shrinking can also be the resultof a membrane being fixed on the layer in question. For example, themembrane may be made out of any material liable to shrink under theeffect of heat, such as microporous polyethylene, hydrophilicpolyurethane, hydrophilic polyester, . . . .

[0060] The laminated material layer in question may optionally besubjected to a coating operation, e.g. being coated in a substance basedon polyurethane, on polyvinyl chloride (PVC), on silicone, . . . , inorder to create the desired effect of shrinkage under the effect ofheat.

[0061] After subjecting such a laminated material to testing of itsability to provide protection against radiant heat in application ofstandard EN 366 and to provide protection against convective heat inapplication of standard EN 367, it has been found that its protectionvalues are high. In addition, the difference between the theoreticalburn times (t2 or HTI 24) and the theoretical pain times (t1 or HTI 12)is improved.

[0062] It is found that these values are indeed greater than the averagegenerally observed for prior art laminates.

[0063] In addition, this result is obtained using a material that ismuch more flexible and that presents much smaller heat load in normaloperation.

[0064] The advantages can clearly be seen from the description. Amaterial is obtained that is much more flexible and comfortable, bothphysically and physiologically, compared with prior art laminates.

[0065] The ability to perceive danger is also improved because this typeof laminate adapts the degree of insulation it provides progressively asa function of the level of thermal danger.

[0066] It may be added that this laminate does not present the agingproblems associated with conventional needled felts (fiber migration,compacting, . . . ), nor does it present the abrasion problems to whichthermal barriers presenting permanent relief are subjected or create.

[0067] In addition, this novel thermal barrier makes it possible to seethe degradation state of the laminate. Since shrinkage takes place onlyunder extreme conditions, it corresponds to a loss of effectiveness ofthe outer fabric, and above all of the membrane which is generallyassociated therewith in this type of garment.

[0068] When the pockets in the double cloth of the invention are in theform of channels, they are preferably disposed vertically in thegarments so as to ensure that the small amount of shrinkage in theperpendicular direction does not raise the bottom of the jacket and thecuffs of the sleeves. This small amount of shrinkage in the layer inquestion on the body of the wearer is not a problem since it leads to aredistribution of the protective air contained inside the garment,leading automatically to enhanced protection at those locations wherespot temperatures are the greatest.

[0069] Naturally, the multilayer laminated material of the invention canadvantageously be combined with a structure that also includes an outerfabric and an internal breathing membrane generally associated with asubstrate and complying with the general dispositions shown in FIG. 1.

1. A multilayer laminated sheet material usable for making protectivegarments, in particular for firefighters, and enabling a thermal barrierto be made comprising first and second layers for use in making suchgarments, the material being made by weaving or knitting, in such amanner as to form a structure comprising two superposed facesintermittently interconnected to each other so as to form pockets, andin which: one of the layers shrinks under the effect of heat; and thelinking between the layers is implemented by intermittently linkingselected yarns so as to form said pockets.
 2. A laminated materialaccording to claim 1, wherein the layer that shrinks under the effect ofheat is constituted completely or in part by yarn that shrinks undersaid effects of heat.
 3. A laminated material according to claim 1,wherein the pockets constitute channels, with shrinking under the effectof heat taking place only in the family of yarns that extendperpendicularly to said channels, considered in full or in part.
 4. Alaminated material according to claim 1, wherein the shrinking effect ofthe layer in question is the result of the presence of a membrane fixedon said layer, said membrane being made of a material which is suitablefor causing it to shrink under the effect of heat.
 5. A laminatedmaterial according to claim 1, wherein the shrinking effect of the layerin question is the result of the presence of a coating on said layer ofa material suitable for shrinking under the effect of heat.
 6. Alaminated material according to claim 1, wherein the structure ratiobetween the two layers lies in the range one-to-one to one-to-ten.
 7. Acomplex material according to claim 1, the material being combined withan outer fabric and a breathing membrane associated with a substrate.